Analyses of radon gas tracer
measurements and observation of the variability of thermal structures have long
been thought to indicate the presence of weak air currents in Niedzwiedzia (Bear)
Cave, Kletno, Poland. However, only after ultrasonic anemometers were installed
could different circulation systems of varying origin and the expected air movements
be observed by direct measurement. This paper presents: a) the different methods
applied in order to determine the weakest air currents both directly and indirectly;
b) a summary of hypotheses on the subject; and c) the first results that air
indeed moves in so-called static areas and that visitors affect both cave airflow
and temperature. First results show that even in so-called static caves or within
corresponding parts of cave systems, the term “static“ has to be
regarded as wrong with respect to the air currents as no situation where no
air movements took place could be proven so far within the caves. Moreover,
the influence of passing tourist groups on the cave climate could unequivocally
be identified and demonstrated.